Cartridge with locking knife for a curved cutter stapler

ABSTRACT

A surgical instrument adapted for applying a plurality of surgical fasteners to body tissue includes a cartridge module having a cartridge housing containing a plurality of surgical fasteners and a knife. The cartridge module includes a driver disposed to push surgical fasteners out of the cartridge housing. The instrument also includes a firing mechanism associated with the cartridge housing for ejecting the surgical fasteners and the knife from the cartridge housing. The knife includes a detent disposed to contact a mating detent of the cartridge module during longitudinal travel of the knife thereby preventing undesired forward and rearward motion of the knife. The driver includes a detent disposed to contact at least one mating detent formed on the cartridge module.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon U.S. Provisional Patent Application No.60/532,911, filed Dec. 30, 2003, entitled “STAPLER CARTRIDGE FOR ACURVED CUTTER STAPLER”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a surgical stapling and cuttinginstrument adapted for use in the diagnosis and therapy of pathologiestreated by stapled resection. More particularly, the invention relatesto a cartridge module for surgical stapling and cutting instruments thatincludes detents for the driver and knife assemblies.

2. Description of the Prior Art

Surgical stapling and cutting instruments are commonly utilized in thediagnosis and treatment of pathologies treated by stapled resection.Surgical stapling and cutting instruments provide a mechanism to extendthe transluminal exploitation of mechanical suturing devices introducedvia the anal canal, mouth, stomach and service accesses. Althoughsurgical stapling and cutting instruments are most commonly utilizedwith rectal pathologies, surgical stapling and cutting instruments maybe used in a variety of environments.

Over time, surgical stapling and cutting instruments have beendeveloped. These instruments generally include a support frame, an anvilattached to the support frame and a cartridge housing carrying aplurality of staples. The instruments also include a driver within thecartridge housing which pushes all of the staples out simultaneouslyinto the anvil to form the staples into a generally B-shape, suturingtissue together. In addition, these instruments include approximationmechanisms for moving the cartridge housing from a spaced position fromthe anvil to accept tissue therebetween to a closed position where thetissue is clamped between the anvil and the cartridge housing. Finally,the devices include a firing means for moving the driver forward to formthe staples against the anvil.

Many of these instruments rely upon replaceable cartridge modulesincluding a plurality of staples. These replaceable cartridges permitmultiple usage of surgical stapling and cutting instruments by simplyreplacing the cartridge modules after each staple procedure. Mostcartridge modules include a staple driver and a knife assembly. Bothassemblies slide within the cartridge housing when the device is fired.Prior to use, the staple driver assembly and the knife assembly must beheld in a retracted position within the cartridge module. The structureholding the staple driver assembly and knife assembly in this positionmust be strong enough to prevent movement during shipping. Movement ofthe staples out of their pockets may lead to staples falling out orbeing out of position, both of which may lead to bleeding staple linesor worse. Movement of the knife assembly to a position where the knifeis exposed might cause injury to anyone using the device or aninadvertent cut in tissue during use on a patient.

After firing of the cartridge module, the staple driver assembly mustremain in its forward fired position. The stapler driver assembly isretained in this position to ensure that the spent cartridge lockoutassembly is activated. The staple driver assembly is also retained inthis position such that the driver tips remain visible providing theuser with a visible clue that the cartridge module is spent.

The knife assembly must be retracted and held within the cartridgehousing after the device is fired and the trigger is released. Thestructure that holds the knife assembly in the retracted position mustwithstand the forces experienced during reloading so that the knifecutting edge is not exposed.

Since the cartridge module may be fired several times duringmanufacturing, the structures that hold the driver assembly and theknife assembly within the cartridge module must be durable enough towithstand repeated cycling. The force required to reset the stapledriver assembly and the knife assembly to the retracted positions shouldalso be minimized to ease manufacturing and to minimize the kniferetraction force requirement (spring force) for the instrument.

With this in mind, an improved cartridge module providing structure forholding and indicating the position of the staple driver assembly andthe knife assembly is required. The present invention provides such acartridge module.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide asurgical instrument adapted for applying a plurality of surgicalfasteners to body tissue. The surgical instrument includes a cartridgemodule having a cartridge housing containing a plurality of surgicalfasteners and a knife. The cartridge module includes a driver disposedto push surgical fasteners out of the cartridge housing. A firingmechanism is associated with the cartridge housing for ejecting thesurgical fasteners and the knife from the cartridge housing. The knifeincludes a detent disposed to contact a mating detent of the cartridgemodule during longitudinal travel of the knife thereby preventingundesired forward and rearward motion of the knife. The driver includesa detent disposed to contact at least one mating detent formed on thecartridge module.

It is also an object of the present invention to provide a surgicalinstrument wherein the cartridge housing includes a cartridge slotthrough which the detent of the knife extends, the cartridge slotincluding first and second flexible fingers molded into the side of thecartridge housing.

It is another object of the present invention to provide a surgicalinstrument wherein the first and second fingers are oriented parallel tothe longitudinal axis of the cartridge module.

It is a further object of the present invention to provide a surgicalinstrument wherein the first finger is shaped and dimensioned to contactthe detent of the knife.

It is also another object of the present invention to provide a surgicalinstrument wherein the second finger is shaped and dimensioned tocontact the detent of the driver.

It is still another object of the present invention to provide asurgical instrument wherein cam surfaces are positioned along the edgeof each of the first and second fingers.

It is yet another object of the present invention to provide a surgicalinstrument wherein the location of the respective cam surfaces isdetermined by the desired position of the driver or knife duringoperation.

Other objects and advantages of the present invention will becomeapparent from the following detailed description when viewed inconjunction with the accompanying drawings, which set forth certainembodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the linear surgical stapler inaccordance with the present invention.

FIG. 2 is perspective view of the linear surgical stapler with thecartridge module removed.

FIG. 3 is a perspective view of the linear surgical stapler with thecartridge housing moved to an intermediate position.

FIG. 4 is a perspective view of the linear surgical stapler with thecartridge housing moved to a closed position.

FIG. 5 is a perspective view of the linear surgical stapler with thefiring trigger in a firing position.

FIG. 6 is an exploded view of the cartridge module.

FIG. 7 is a front perspective view of the cartridge module with theretainer secured thereto.

FIG. 8 is a front perspective view of the cartridge module with theretainer removed.

FIG. 9 is a rear perspective view of the cartridge module showing thecartridge housing slot in substantial detail.

FIGS. 10, 11 and 12 show the assembly of the retainer.

FIG. 13 is a partial cross-sectional view of the linear surgical staplerin an unactuated orientation.

FIG. 14 is an exploded view of the pin actuation mechanism.

FIG. 15 is a partial cross sectional view of the linear surgical staplerwith the closure trigger slightly retracted.

FIG. 16 is a partial cross sectional view of the linear surgical staplerwith the closure trigger nearly fully retracted.

FIG. 17 is a partial cross sectional view of the linear surgical staplerwith the closure trigger fully retracted.

FIG. 18 is a partial cross sectional view of the linear surgical staplerwith the firing trigger and closure trigger fully retracted.

FIG. 19 is partial cross sectional view of the linear surgical staplerafter the surgeon depresses the release button.

FIG. 20 is a partial cross sectional view of the linear surgical staplerupon release of the closure and firing triggers without returning to anintermediate detent position.

FIG. 21–29 show the insertion of a cartridge module and the removal ofthe retainer.

FIGS. 30–38 show the various steps involved in the actuation of thepresent linear surgical stapler.

FIGS. 39 and 40 are detailed front views of the cartridge housing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The detailed embodiment of the present invention is disclosed herein. Itshould be understood, however, that the disclosed embodiment is merelyexemplary of the invention, which may be embodied in various forms.Therefore, the details disclosed herein are not to be interpreted aslimiting, but merely as the basis for the claims and as a basis forteaching one skilled in the art how to make and/or use the invention.

With reference to the various figures, a surgical instrument 20 adaptedfor applying a plurality of surgical fasteners to body tissue isdisclosed. The surgical instrument 20 includes an anvil 122 and acartridge housing 121 containing a plurality of surgical fasteners and aknife 126. The cartridge housing 121 and anvil 122 are relativelymovable between a first spaced apart position and a second position inclose approximation with one another. The instrument 20 also includes afiring mechanism associated with the cartridge housing 121 for ejectingthe surgical fasteners and the knife 126 from the cartridge housing 121to be driven against the anvil 122. A cartridge module 120, which thecartridge housing 121 forms a part of, includes a driver 131 disposed topush fasteners out of the cartridge housing 121 and a knife holder 130disposed immediately proximal of the driver 131 in the cartridge housing121. The knife holder 130 is attached to the knife 126 that extendsdistally from the knife holder 130 through a slot 200 in the driver andthrough a slot 199 in the cartridge housing 121. The knife holder 130includes a detent post 138 that extends through a slot 137 in thecartridge housing 121. The knife holder detent post 138 is disposed tocontact a detent protrusion 139 of the cartridge slot 137 during thelongitudinal travel of the knife 126 and knife holder 130. The driver131 includes a detent post 140 that is disposed to contact proximal anddistal detent protrusions 141, 142 formed on the cartridge housing slot137.

Referring to FIG. 1 in combination with FIGS. 2 to 5, there is shown asurgical stapling and cutting instrument, in particular, a linearsurgical stapler 20 which is designed to staple and cut tissue. Thelinear surgical stapler 20 has a handle 21 at a first proximal end andan end effector 80 at an opposite distal end. The end effector 80 iscurved in accordance with a preferred embodiment of the presentinvention. Right and left hand structural plates (often called “handleplates”) 34, 35, respectively, connect the handle 21 to the end effector80 of the instrument (the left hand handle plate is not shown in FIG.1). The handle 21 has a right hand shroud 22 coupled to a left handshroud (the left hand shroud is not shown in FIG. 1). The handle 21 alsohas a body portion 23 to grip and maneuver the linear surgical stapler20 (see FIGS. 2 to 5).

The end effector 80 is a surgical fastening assembly that includes acartridge module 120 (see FIGS. 6 to 9) and a C-shaped supportingstructure 81. The term C-shaped is used throughout the specification todescribe the concave nature of the supporting structure 81 and thecartridge module 120. The C-shaped construction facilitates enhancedfunctionality and the use of the term C-shaped in the presentspecification should be construed to include a variety of concave shapeswhich would similarly enhance the functionality of surgical stapling andcutting instruments. The distal end 30 of a closure member 28 isdisposed to receive the cartridge module 120. The end effector 80 alsoincludes a safety lockout mechanism 180 (best seen in FIG. 31) forpreventing the firing of a previously fired cartridge module 120. Thecartridge module 120 contains a cartridge housing 121 coupled to ananvil 122. The cartridge module 120 also includes a retaining pin 125, aknife 126, a removable retainer 160, a tissue contacting surface 127which displays a plurality of staple-containing slots 128 in staggeredformation in one or more rows (that is, staple lines) on either side ofthe knife 126. Staples (not shown) are fired from the cartridge housing121 against staple-forming surface 129 of the anvil 122 that faces thetissue-contacting surface 127 of the cartridge housing 121.

As will become apparent based upon the following disclosure, the presentlinear surgical stapler 20 is designed as a multiple firing device witha replaceable cartridge module 120. However, it should be understoodthat many of the underlying concepts of the present invention may beequally applied in single firing devices without departing from thespirit of the present invention.

The supporting structure 81 of the end effector 80 is respectivelyattached to the right and left handle plates 34, 35, by a shoulder rivet82 and posts 83 which extend from the supporting structure 81 intoreceiving holes in the handle plates 34, 35. In accordance with apreferred embodiment of the present invention, the supporting structure81 is formed via a single piece construction. More specifically, thesupporting structure 81 is formed by extrusion, for example, ofaluminum, with subsequent machining to create the supporting structure81 disclosed in accordance with the present invention. By constructingthe supporting structure 81 in this manner, multiple parts are notrequired and the associated cost of manufacture and assembly issubstantially reduced. In addition, it is believed the unitary structureof the supporting structure 81 enhances the overall stability of thepresent linear surgical stapler 20. In addition, the unitary extrudedstructure of the supporting structure 81 provides for a reduction inweight, easier sterilization since cobalt irradiation will effectivelypenetrate the extruded aluminum and less trauma to tissue based upon thesmooth outer surface achieved via extrusion.

The handle 21 of the linear surgical stapler 20 includes a hand grip 24which the surgeon grasps with the palm of his hand (see FIGS. 2–5). Thehand grip 24 is composed of a right hand shroud handle 25 (see FIG. 1)and a left hand shroud handle (the left hand shroud handle is not shownin FIG. 1). Pivotally extending from the underside of the handle 21 area closure trigger 26 and a firing trigger 27. The linear surgicalstapler 20 illustrated in FIG. 1 is shown with the closure and firingtriggers 26, 27 in their unactuated positions and with a cartridgemodule 120 inserted and the retainer 160 removed. Consequently, thecartridge housing 121 is spaced from the anvil 122 for the placement oftissue between the cartridge housing 121 and the anvil 122.

The handle 21 of the linear surgical stapler 20 contains a tissueretaining pin actuation mechanism 100. The tissue retaining pinactuation mechanism 100 includes a saddle shaped slide 101 positioned onthe top surface of the handle 21. Manual movement of the slide 101results in distal movement of the push rod 102. The push rod 102 iscoupled to the retaining pin 125 of the cartridge module 120. The distalmovement or proximal retraction of the push rod 102 results incorresponding movement of the retaining pin 125. The retaining pinactuation mechanism 100 is also releasably coupled to the closuretrigger 26 within the handle 21 such that actuation of the closuretrigger 26 will result in automatic distal movement of the retaining pin125 if it has not already been manually moved to its most proximalposition.

Referring briefly to FIGS. 2 to 5, there is illustrated what happenswhen the cartridge module 120 is loaded and the closure and firingtriggers 26, 27 are sequentially squeezed toward the hand grip 24 toactuate the end effector 80 of the linear surgical stapler 20. Thelinear surgical staple 120 is loaded with the cartridge module 120, asshown in FIG. 2, and the retainer 160 is removed. The linear surgicalstapler 20 is now ready to receive tissue as shown in FIG. 1.

When the closure trigger 26 is partially squeezed to rest in its firstdetent position shown in FIG. 3, the cartridge housing 121 moves fromits fully opened position to an intermediate position between the openand closed positions as discussed below in greater detail.Simultaneously, the tissue retaining pin actuation mechanism 100 movesthe retaining pin 125 forward from the cartridge housing 121 through anopening in the anvil 122. In this position, tissue which has been placedbetween the cartridge housing 121 and the anvil 122 can be properlypositioned, and the retention of the tissue between the cartridgehousing 121 and the anvil 122 is assured. Therefore, when the closuretrigger 26 has been actuated to its intermediate position, the cartridgehousing 121 and anvil 122 are correspondingly positioned in their tissueretaining positions.

When the closure trigger 26 is fully squeezed so that it is adjacent theforward end of the hand grip 24, as illustrated in FIG. 4, the tissuecontacting surface 127 of the cartridge housing 121 and thestaple-forming surface 129 of the anvil 122 are adjacent to each other,and the properly positioned and retained tissue is consequently fullyclamped. Additionally, the firing trigger 27 has rotatedcounterclockwise toward the handgrip 24 to enable the surgeon to graspthe firing trigger 27 for the firing of staples. Accordingly, the firingtrigger 27 is now in position for the surgeon to squeeze it to stapleand cut the tissue. When the firing trigger 27 has been fully squeezedto fire the staples, as shown in FIG. 5, the firing trigger 27 rests innear proximity to the closure trigger 26.

Referring now to FIGS. 6 to 9, a more detailed description of thecartridge module 120 is presented. The present cartridge module 120provides a cutting and sealing mechanism for utilization within thelinear surgical stapler 20 wherein the stapling and cutting functionsoperate in the same direction during device actuation. Although thepresent cartridge module 120 is particularly adapted for use inconjunction with linear surgical stapling devices, the concepts of thepresent cartridge module 120 may be applied to other surgical deviceswithout departing from the spirit of the present invention. Inparticular, the present cartridge module 120 provides that the knife 126be utilized in conjunction with a corresponding washer 123 during thecutting process. The present cartridge module 120 ensures that multiplefirings of the linear surgical stapler 20 will not compromising cuttingperformance. This is accomplished by incorporating the anvil 122, inparticular, the cutting washing 123, with the cartridge module 120. Bycombining the washer 123 with the cartridge module 120, a new washer 123is provided each time the cartridge module 120 is replaced, resulting inimproved cutting performance.

Enhanced performance is further provided by positioning the anvil 122and the cartridge housing 121 parallel such that they move relative toeach other with the facing surfaces of the anvil 122 and the cartridgehousing 121 maintained in a parallel orientation. This provides for aneven distribution of pressure across the tissue, preventing squeezing ofthe tissue in a manner which might bunch the tissue and force portionsof the tissue out of the desired spaced defined between the anvil 122and the cartridge housing 121.

More specifically, he cartridge module 120 includes a cartridge housing121 that contains a plurality of staples (not shown) positioned instaple-containing slots 128. Immediately behind the staples is disposeda driver 131 which is disposed to push the staples out of the stapleslots 128. A knife holder 130 is disposed immediately proximal of thedriver 131 in the cartridge housing 121. The knife holder 130 contains aslot 172 and ledge 173 for interaction with a knife retractor hook 45(see FIG. 37) in a manner which will e discussed below in greaterdetail. The knife holder 130 is attached to the knife 126 that extendsdistally from the knife holder 130 through a slot 200 in the driver 131and through a slot 199 in the cartridge housing 121. Although the knifeis disclosed as being within the housing in accordance with a preferredembodiment of the present invention, other configurations may beemployed without departing from the spirit of the present invention; forexample, it is contemplated that the cartridge module could beconstructed without a knife if specific applications so dictate.

The knife holder 130 has a detent post 138 that extends through a slot137 in the cartridge housing 121. The knife holder detent post 138 isdisposed to contact detent protrusion 139 of the cartridge slot 137during the longitudinal travel of the knife 126 and the knife holder130. Similarly, the driver 131 has a detent post 140 that is disposed tocontact proximal and distal detent protrusions 141, 142, respectively,of the cartridge slot 137. The detent posts 138, 140 of the knife holder130 and the driver 131 provide a mechanism for controlling movement ofthe knife holder 130 and the driver 131. That is, the interactionbetween the detent post 138 of the knife holder 130 interacts withdetent protrusion 139 to control movement of the knife holder 130between a prefired and a retracted position, while the interactionbetween the detent post 140 of the driver 131 interacts with theproximal and distal detent protrusions 141, 142 to control movement ofthe driver between a prefired and retracted position.

In addition, and further to the other functions described below, thecontrol mechanism provided by the detent posts 138, 140 and the detentprotrusions 139, 141, 142, maintains the knife holder 130 in a desiredposition and maintains the driver 131 in a desired position afterfiring. Before use, this mechanism prevents the driver 131 from movingso that staples aren't fired until the doctor desires. In addition, thepresent mechanism prevents knife 126 from falling out the backside ofthe cartridge housing 121.

In accordance with a preferred embodiment, the cartridge housing 121includes two separate detents ports for the driver 131 and the knifeholder 130. In particular, driver detent port 140 is integrally formedwith the driver 131 and the knife detent port 138 is integrally formedwith the knife holder 130. The driver detent port 140 and the knifeholder detent port 138 are shaped and dimensioned to interface withfirst and second flexible fingers 167, 168 molded into the side of thecartridge housing 121.

The first and second fingers 167, 168 are oriented parallel to thelongitudinal axis of the cartridge module 120. The first finger 167 isshaped and dimensioned to contact the knife detent post 138 of the knifeholder 130 and the second finger 168 is shaped and dimensioned tocontact the driver detent post 140 of the staple driver 131. Protrusions139, 141, 142, as discussed above, are positioned along the edge of eachof the first and second fingers 167, 168. The location of the respectiveprotrusions 139, 141, 142 is determined by the desired position of thedriver 131 or knife holder 130 during operation. The shape of theprotrusions 139, 141, 142 and the thickness of the flexible fingers 167,168 are determined by the desired retention forces.

The present cartridge module 120 offers a variety of advantages. Forexample, compliance of the flexible fingers makes multiple cyclespossible without loss of detent force and detent force can be “tuned in”by modifying the protrusion surfaces or cross sections of the fingers.In addition the protrusion surfaces allow different extension andretraction detent forces. For example, the force to overcome the knifedetent post 138 during firing can be made to be significantly higherthan the force to retract the knife 126 past the same detent post.

It is also an advantage of the present cartridge module 120 that theindependent detents posts 138, 140 for the knife holder 130 and driver131 allow the driver 131 to be held in an extended “fired” position asthe knife 126 is retracted and retained in the unfired position. Sincethe knife 126 must slide through the staple driver 131 as it retracts,the staple driver detent post 140 ensures that the friction with theknife 126 does not cause the driver 131 to retract with the knife 126.If the driver 131 were to retract, the spent cartridge lockout mechanism180 would not engage, causing a possibly hazardous situation.

In addition, the positioning of the detents posts 138, 140 on the sideof the cartridge housing 121 give a visual indication of the position ofthe driver 131 and knife holder 130 within the cartridge housing 121. Italso provides access to the detents posts 138, 140 so that they may bedeflected in order to reload the cartridge module 120.

The knife 126 and slots 199, 200 are positioned such that there is atleast one row of staples on either side of the knife 126. In accordancewith a preferred embodiment of the present invention, two rows of stapleslots 128 (and two rows of staples) are provided on each side of theslot 199 of the cartridge housing 121.

The cartridge housing 121 contains two generally circular openings 143,144 at either end of the knife slot 199. The general circular opening143 at the base of the cartridge housing 121 is shaped and dimensionedfor the passage of a guide pin 124 through the cartridge housing 121.The generally circular hole 144 at the top of the cartridge housing 121is shaped and dimensioned for the passage of a retaining pin 125 throughthe cartridge housing 121. The staple slots 128 are arranged such thatthe staples laterally extend past the generally circular holes 143, 144.

In accordance with a preferred embodiment of the present invention, theanvil 122 includes a plastic washer 123 and a metallic staple-formingsurface 129. The anvil 122 is disposed to contain staple-forming surface129 in a matching configuration with the staples. The retaining pin 125is connected to a coupler 133 by a circumferential slot 135 in theretaining pin 125 and a groove 134 in the coupler 133 (best seen in FIG.14). The coupler 133 is disposed within an arm 145 of the cartridgehousing 121 and is held into the arm 145 by an end cap 146.

The guide pin 124 and retaining pin 125 include respective slots 147 a,147 b (best seen in FIGS. 8, 9, 36, 39 and 40) into which the ends 126a, 126 b of the knife 126 are disposed. The proximal end 148 of theguide pin 124 is connected to the proximal end 149 of the anvil 122. Thedistal end 150 of the guide pin 124 extends from the cartridge housing121 and extends through a slot 151 of the anvil 122. A cutting washer123 slips onto the anvil 122 by means of a groove 152 on the anvil 122that fits under a tongue 153 on the washer 123. The opposite end 154 ofthe cutting washer 123 slips under the anvil arm 155 and is pinned tothe anvil arm 155 by a pin 156. In this position, the cutting surface157 of the washer 123 extends up through a slot 151 of the anvil 122.The assembly of the cutting washer 123 to the anvil 122 traps the guidepin 124 into the opening formed by the anvil slot 151 and the cuttingsurface 157, thereby, operatively connecting the anvil 122 to thecartridge housing 121. The retainer 160 is attached to the cartridgemodule 120 as shown in FIG. 7 to hold the components of the cartridgemodule 120 in a desired orientation until insertion into the endeffector 80.

Turning to FIGS. 6 to 12 in combination with FIGS. 25 to 29, theretainer 160 will be described in more detail. The retainer 160 has agroove 161 that is disposed around a protrusion 159 of the cartridgehousing 121. The retainer 160 contains a resilient inner spring arm 162that is disposed for reciprocating movement within the retainer 160. Theretainer 160 includes containment slots 163 which extend partiallyaround the guide pin 124. The spring arm 162 includes containment slots164 which extend partially around the guide pin 124, but are configuredto face in an opposing direction to the containment slots 163. Theretainer 160 is positioned onto the cartridge module 120 such that thecontainment slots 163, 164 surround the guide pin 124 and trap theretainer 160 onto the cartridge module 120. The spring arm 162 includesa disengagement tab 165 which extends down from the retainer 160 belowthe anvil arm 155. As such, the retainer 160 is not easily removed fromthe cartridge module 120 until the cartridge module 120 is properlyseated within the end effector 80. Upon proper seating of the cartridgemodule 120 within the end effector 80, the disengagement tab 165 engagesthe end effector 80 for release of the retainer 160.

Referring once again to FIG. 1 in combination with FIG. 2 and FIG. 13, amore detailed description of the components of the linear surgicalstapler 20 is provided. The linear surgical stapler 20 includes anelongated closure member 28, with a generally C-shaped cross section,extending from the handle 21 into the surgical fastening assembly of theend effector 80. In accordance with a preferred embodiment of thepresent invention, the closure member 28 is a molded plastic membershaped for movement and functionality in accordance with the presentinvention. By manufacturing the closure member 28 from plastic,manufacturing costs are reduced and the weight of the linear surgicalstapler 20 is also reduced. In addition, the linear surgical stapler 20is easier to sterilize with cobalt irradiation as plastic is easier topenetrate than stainless steel. In accordance with an alternateembodiment, the closure member may be made from extruded aluminum withthe final features machined into place. While an extruded aluminumclosure member might not be as easy to manufacture as the plasticcomponent, it would still have the same advantages (i.e., elimination ofcomponents, easier to assemble, lower weight, easier to sterilize).

The distal portion of the closure member 28 passes through the walls 84of the supporting structure 81. The distal end is disposed to receiveand retain the cartridge housing 121 of the cartridge module 120. Thecentral portion of the closure member 28 is positioned between the rightand left handle plates 34, 35, respectively. Right and left hand closurelinks 36, 37, respectively, are pivotally attached at the right and leftproximal ends of the closure member 28 by a first integral closure linkpin 38. At the opposite end of the closure links 36, 37, the closurelinks 36, 37 are pivotally attached to a second integral closure linkpin 39. The second integral closure link pin 39 connects the closurelinks 36, 37 to a slotted closure arm link 40. The slotted closure armlink 40 is pivotally mounted to the handle plates 34, 35 of the linearsurgical stapler 20 at a closure trigger pivot pin 41. The closuretrigger 26 descends from the slotted closure arm link 40 for pivotalrotation about the closure trigger pivot pin 41 toward and away from thehandgrip 24. A closure spring 42 housed within the hand grip 24 of thehandle 21 is secured to the slotted closure arm link 40 to provide adesired resistance when the surgeon squeezes the closure trigger 26toward the handle grip 24, and to bias the closure trigger 26 toward theopen position.

Referring to FIGS. 13 and 14, the components of the retaining pinactuation mechanism 100 will now be described. The handle 21 contains asaddle shaped slide 101 mounted on top of the handle 21 for linearmotion. The slide 101 is connected to a post 103 that extends outwardfrom a push rod driver 104 through slots 105 (see FIG. 2) in the handle21. The push rod driver 104 is restrained for longitudinal movementalong the long axis of the linear surgical stapler 20 by slots 105. Thepush rod driver 104 is connected to the push rod 102 by acircumferential groove 107 on the push rod 102 that snaps into a slot108 of the push rod driver 104. The distal end of the push rod 102contains a circumferential groove 109 that interconnects with a groove132 in the proximal end of the coupler 133 of the cartridge module 120(best seen in FIG. 22). The distal end of the coupler 133 contains agroove 134 for interconnecting with a circumferential slot 135 on theretaining pin 125.

The closure member 28 contains posts 29 which extend laterally on bothsides of the closure member 28 inside the handle 21. These posts 29slidably connect to an L-shaped slot 110 of a yoke 111. The yoke 111 ispivotally mounted to the handle 21 by a pivot pin 112 on the yoke 111.The yoke 111 contains cam pins 113 positioned to push camming surfaces114 on the push rod driver 104.

Referring to FIG. 13 and FIG. 37, the components of the firingtransmission assembly will now be described. The firing transmissionassembly has an elongated firing bar 43 extending from the handle 21into the surgical fastening assembly of the end effector 80. The firingbar 43 is positioned within the C-shaped cross section of the closuremember 28. The distal end of the firing bar 43 extends into thecartridge housing 121 and is positioned just proximally of the knifeholder 130 and driver 131. The distal end of the firing bar 43 isattached to a knife retractor 44 that has a knife retraction hook 45.

The firing bar 43 has a rectangular receiving slot 46 in that portion ofthe ring bar 43 that is housed within the handle 21 (see FIG. 13). Thefirst integral closure link pin 38 extends through the receiving slot46. The firing bar 43 also has a proximal end section 47. The undersideof the proximal end section 47 of the firing bar 43 has a slidingsurface 48. The proximal end section 47 also has a terminal sideengagement surface 49 extending from the sliding surface 48. The firingtrigger 27 is pivotally mounted to the handle plates 34, 35 by a firingtrigger pivot pin 50 spaced from the closure trigger pivot pin 41 sothat each of the pivot pins pivot about mutually independent axes. Thefiring trigger 27 includes an arcuate firing trigger link 51 extendingfrom the firing trigger 27 at the firing trigger pivot pin 50 to an apex52 which rests on the sliding surface 48 of the proximal end section 47of the firing bar 43. Within the handle 21, the firing trigger 27 isattached to first and second firing trigger spring arms 53, 54,respectively. The firing trigger spring arms 53, 54 support a torsionspring (not shown) on the right half of the firing trigger 43. Finally,a firing bar return spring 55 is secured to the underside of the firingbar 43 at that portion of the firing bar 43 within the handle 21 to biasthe firing bar 43 toward its unactuated position.

When the closure trigger 26 is squeezed toward the handgrip 24, theslotted closure arm link 40 and the closure links 36, move distallywithin the receiving slot 46 of the firing bar 43. This distal movementcauses the closure member 28 to correspondingly move distally. Likewise,the firing bar 43 concurrently moves distally with the closure member 28because the first integral closure link pin 38, to which the closurelinks 36, 37 are attached, extends through the receiving slot 46 in thefiring bar 43.

The mechanism which defines an intermediate closure detent position andthe release of the closure trigger 26 from an actuated position to itsoriginal unactuated position will now be described in connection withFIG. 1 in combination with FIGS. 13–20. The top side of the slottedclosure arm link 40 has a clamp sliding surface 56 that displays anintermediate detent 57 and a closure detent 58. A release pall 59 slideson the clamp sliding surface 56 and may engage the intermediate andclosure detents 57, 58. The release pall 59 has a laterally extendingpall lug 60 (best seen in FIG. 1) at its distal end. The release pall 59is located within the handle 21, and it is integrally attached to arelease button 61 situated exteriorly of the handle 21. The releasebutton 61 has a thumb rest 62, and the release button 61 is pivotallyattached to the handle 21 by a release trunnion 63. The release button61 is biased outwardly from the handle 21 and, therefore, the releasepall 59 is biased downwardly toward the clamp sliding surface 56 by arelease spring 64 which is mounted to the handle 21 by a springretention pin 65 and mounted to the release button 61 by a button springpost 66. The slotted closure arm link 40 has an arcuate recess 67located between the intermediate and closure detents 57, 58. Sittingwithin this arcuate recess 67 for rotational movement are a left handtoggle 68 integrally connected to a right hand toggle (the tight handtoggle is not shown). Each toggle 68 has a toggle arm 69 that isengageable with the pall lug 60. The pall lug 60 has a concave proximalsurface 70 to provide clearance between the toggle arm 69 and the palllug 60.

Referring to FIG. 31 (cut away view into cartridge and supportingstructure), the components of the fired device lockout mechanism 180will now be described.

As will be appreciated based upon the following disclosure, once thedevice has been fired the lockout mechanism 180 prevents movement of thecartridge housing 121 to its second closed position but permittingrelative reapproximation movement of the cartridge housing 121 and anvil122, whereby reapproximation provides an indicator that the instrumentis not malfunctioning. Permitted reapproximation will constituteapproximately ¼ to approximately ⅔ of the total distance between thecartridge housing 121 and the anvil 122 when in the first spaced apartposition, and more preferably, ¼, ⅓, or ½ of the total distance betweenthe cartridge housing and the anvil when in the first spaced apartposition.

The lockout mechanism 180 contains a lockout lever 181 that is pivotallymounted to the distal end 30 of the closure member 28 by a pin 182. Thelockout lever 181 is spring biased down toward the base of supportingstructure 81 by a spring (not shown). The lockout lever 181 contains aproximal and distal end 184, 185, respectively. The proximal end 184 hasa cam surface 186 and locking groove 187. The supporting structure 81 ofthe end effector 80 contains a ledge 85 that is disposed to interactwith locking groove 187 when the lockout mechanism 180 is engaged. Thesupporting structure 81 contains a base surface 86 between walls 84. Thebase surface 86 is disposed to interact with cam surface 186 when thelockout lever 181 is not engaged.

The operation of loading the cartridge module 120, the closuremechanism, the retaining pin mechanism, the firing transmissionassembly, the intermediate and closure detents 57, 58, the releasemechanism, and the lockout mechanism 180 will now be described.Referring to FIGS. 7 to 12 and FIGS. 21 to 28 the loading of thecartridge module 120 into the tissue end effector 80 is described. Thecartridge module 120 is shaped and dimensioned for selective insertionand removal from the tissue end effector 80 of the linear surgicalstapler 20.

Prior to insertion of the cartridge module 120 into the end effector 80of the linear surgical stapler 20, as seen in FIG. 7, the retainer 160can not easily be removed from the cartridge module 120 as the groove161 is disposed around the protrusion 159 at the top end of the retainer160 preventing disconnection. Further, the containment slots 163, 164 ofthe retainer are disposed around the guide pin 124 at the bottom of theretainer 160 preventing disconnection as shown in FIG. 25. The attachedretainer 160 provides support to the structure of the cartridge module120 and an extended surface area for gripping, both features makingloading easier. The retainer 160 also prevents staples from dislodgingfrom the cartridge housing 121 during casual handling and prevents theknife 126 from accidental exposure during casual handling.

Knife 126 movement and staple movement are further resisted prior toloading and during loading by a series of detents. Referring to FIG. 9,detent post 138 on the knife holder 130 is prevented from proximal anddistal movement by the detent protrusion 139 on the cartridge housingslot 137. The driver 131 is prevented from distal movement due to casualhandling and during loading of the cartridge module 120 into the linearsurgical stapler 20 by the interaction of the detent post 140 and thedetent protrusion 141 on the cartridge housing slot 137.

The cartridge module 120 is loaded into the tissue effector 80 such thatthe cartridge housing 121 slips into the distal end 30 of the closuremember 28 as seen in FIGS. 21 to 24. Walls 31 a and 31 b on the closuremember 28 slip into slots 170 a, 170 b of the cartridge housing 121during loading. Simultaneously, tabs 174 (See FIG. 8) slip into groove88 of the C-shaped supporting structure 81. Loading of the cartridgemodule 120 is completed when the detents 171 snap onto the detent groove32 of the closure member distal end 30, as shown in FIGS. 21 to 24.

In the position shown in FIG. 24, the cartridge module 120 is fullyloaded and the proximal groove 132 of the coupler 133 has engaged thedistal circumferential groove 109 of the push rod 102 such that theretaining pin 125 in the cartridge module 120 has been connected to theretaining pin advancement mechanism 100. The slot 172 of knife holder131 engages the knife retraction hook 45 during loading such that thehook 45 has engaged the retraction ledge 173 on the knife holder 130 atthe completion of the cartridge module 120 loading.

At the completion of the cartridge module 120 loading a post 188positioned on driver 131 contacts the distal end 185 of the lockoutlever 181 (see FIG. 31). This contact pivots the lockout lever 181 aboutthe lockout lever pin 182 to a position such that the camming surface186 is horizontally aligned with the base surface 86 of the C-shapedsupporting structure 81.

The retainer 160 can now be removed from the end effector 80.Specifically, completion of loading the cartridge module 120 causes thedisengagement tab 165 to contact the supporting structure 81 (See FIG.23), resulting in an upward movement of the spring arm 162 when thecartridge module 120 is fully loaded as in FIG. 24. This upward movementdisplaces containment slots 164 upward such that the guide pin 124 is nolonger contained (see FIGS. 25 and 26). Referring now to FIGS. 27 to 29,a removal force applied to the thumb pad 166 results in the retainer 160pivoting outward about protrusion 159 until the groove 161 is able toslip off protrusion 159. Removal of the retainer 160 allows for theloaded linear surgical stapler 20 to be utilized.

In FIG. 15, the closure trigger 26 has been partially squeezed from itsopen, unactuated position illustrated in FIGS. 1 and 13. When theclosure trigger 26 is partially squeezed, it pivots about the closuretrigger pivot pin 41 in a counterclockwise direction toward the handgrip24. As it pivots, the slotted closure arm link 40 and closure plateclosure links 36, 37 move forwardly, consequently moving the closuremember 28 and firing bar 43 distally. As the slotted closure arm link 40moves forwardly, the pall lug 60 of the release pall 59 slides on theclamp sliding surface 56. The pall lug 60 engages the distal ends of thetoggle arms 69 of the toggles 68, and consequently pivots the toggles 68in a clockwise direction. As the slotted arm closure link 40 continuesto move forwardly in response to the pivotal movement of the closuretrigger 26 toward the handgrip 24, the pall lug 60 of the release pall59 will eventually lodge into the intermediate detent 57. Oncepositioned in the intermediate detent 57, the closure spring 42 isincapable of returning the closure trigger 26 to its original,unactuated position. The closure trigger 26 is now in its intermediate,partially closed position, to properly position and retain tissuebetween the cartridge housing 121 and anvil 122, as shown in FIG. 15. Inaddition, as the closure member 28 and firing bar 43 move distally, theapex 52 of the arcuate firing trigger link 51 slides on the slidingsurface 48 of the proximal end section 47 of the firing bar 43.

During the closing stroke from the open to the intermediate position theretaining pin mechanism 100 is activated. Forward movement of theclosure member 28 moves the integral posts 29 distally. The posts 29contact the L-shaped slot 110 of the yoke 111. Hence, distal movement ofthe posts 29 cam the L-shaped slot 110 causing the yoke to pivot aroundpins 112. The rotation brings bearing posts 113 on the yoke 111 intocontact with camming surfaces 114 on the push rod driver 104. Furtherrotational movement of the yoke 111 causes bearing posts 113 to move thepush rod driver 104 distally through camming contact on surfaces 114.The push rod driver 104 contacts the push rod 102, moving the push rod102 distally. The push rod 102, in turn, moves the coupler 133 andretaining pin 125 distally. Completion of the closing stroke to theintermediate detent 57 position results in the retaining pin 125 movingdistally through the hole 144 of the cartridge housing 121, through hole159 running through the washer 123 and anvil 122 and into the hole (notshown) in the supporting structure 81. Tissue, which was disposedbetween the contact surface 127 of the cartridge housing 121 and theanvil 122, is now trapped between retaining pin 125 and the guide pin124.

This same result can be obtained prior to closing by manual distalmovement of saddle slide 101. Slide movement will result in forwardmovement of the push rod 102, coupler 133 and retaining pin 125 untilthe retaining pin 125 is fully disposed through the anvil 122, washer123 and hole 89 in the supporting structure 81. Activation of theclosing stroke after the retaining pin 125 has been manually movedforward would still result in the rotation of the yoke 111 as describedabove but without any additional movement of the retaining pin actuationmechanism 100.

The closing stroke from the open to the intermediate detent 57 positionmoves the lockout lever 181 distally as it is attached to closure member28 by the pin 182 as shown in FIG. 31 (open) and FIG. 32 (intermediateposition). Distal movement of the lockout lever 181 causes the cammingsurface 186 to contact the lockout ledge 85 of the support 81, resultingin the lockout lever 181 rotating clockwise and coming to slidablecontact with base surface 86 of supporting structure 81. In thisposition, the distal end 185 of the lockout lever 181 has rotated awayfrom post 188 on driver 131.

Referring now specifically to FIG. 16, when the closure trigger 26 issqueezed toward the handgrip 24 from the intermediate detent 57position, the toggle arms 69 of the toggle 68 disengage from the palllug 60. Consequently, as the toggle 68 continues to rotate in aclockwise direction, the release pall lug 60 rides up the toggle arms 69and with continued motion of the closure trigger 26 falls into theclosure detent 58. As the release pall 59 rides up the toggle arm 69 itrotates the release button 61 clockwise around pivot 63. As the releasepall 60 falls into closure detent 58, it makes an audible clicking soundalerting the surgeon that closure position has been reached.

In addition, as the firing bar 43 continues to move forwardly, the apex52 of the arcuate firing trigger link 51 comes into contact with theside engagement surface 49 of the proximal end section 47 of the firingbar 43. Consequently, the firing trigger 27 is moving into a positionwhere it can continue to move the firing bar 43 distally to fire staplesafter the tissue has been fully clamped. When the apex 52 of the arcuatefiring trigger link 51 moves into engagement with the engagement surface49 of the proximal end section 47, the firing trigger 27 begins topivotally rotate in a counterclockwise direction toward the hand grip 24in response to the action of a torsion spring on the right hand side ofthe firing trigger 27 (torsion spring not shown). The firing trigger 27pivots independently of the pivotal movement of the closure trigger 26,but its pivotal rotation is blocked until the firing bar 43 has moveddistally to enable engagement of the firing trigger link 51 with theterminal engagement surface of the firing bar 43.

Turning specifically to FIG. 17, when the closure trigger 47 has beenfully squeezed and it is adjacent the handgrip 24, the pall lug 60 atthe distal end of the release pall lodge 59 into the closure detent 58.In the closure detent 58 position, the tissue has been fully clampedbetween the cartridge housing 121 and anvil 122, and the closure spring42 is incapable of returning the closure trigger 26 to its originalposition. Therefore, the closure trigger 26 is retained in the positionshown in FIG. 4.

Concurrently with the counterclockwise motion of the closure trigger 26,the firing trigger 27 continues to rotate counterclockwise by the actionof the torsion firing bar return spring 55 until the firing trigger 27is in a relatively vertical orientation with respect to the handle 21 ofthe linear surgical stapler 20. In the fully clamped position, the apex52 of the arcuate firing trigger link 51 has fully engaged theengagement surface of the proximal end section 47 of the firing bar 43and, therefore, the firing trigger 27 is in a position to further movethe firing bar 43 distally to fire staples into the tissue.

In the fully closed position the staple pockets 128 of the cartridgehousing 121 are aligned with the staple-forming surface 129 of the anvil122 as shown in FIG. 33. The retaining pin 125 has aligned the top ofthe anvil 122 and the cartridge housing 121 and the guide pin 124 hasaligned the bottom of the cartridge housing 121 with the bottom of theanvil 122.

As illustrated in FIG. 18 and FIG. 34, the firing trigger 27 can besqueezed to pivotally rotate it toward the hand grip 24 until it ispositioned adjacent the closure trigger 26. During the pivotal rotationof the firing trigger 27, the firing bar 43 moves distally, contacts theknife holder 130. The resulting distal movement of the knife holder 130results in contact with the knife 126 and driver 131. Distal movement ofthe driver 131 results in the staples (not shown) to be distallyadvanced into the staple forming surfaces 129 of the anvil 122 resultingin staple formation of a generally B shape. The knife 126 distallyadvances in slots 147 of the guide pin 124 and the retaining pin 125 inconjunction with staple formation. These slots 147 guide the knife 126onto the cutting surface 157 of cutting washer 123 resulting in thetransection of any tissue caught between.

Release of manual pressure to the firing trigger 27 results in thefiring bar return spring 55 to retract the firing bar 43 and returns thefiring trigger 27 to the position shown in FIG. 17. This movementresults in the retraction hook 45 retracting the retraction ledge 173 onthe knife holder 130 and knife 126. The resulting proximal movementretracts the knife 126 into the cartridge housing 121 as shown in FIG.35. Detent post 138 on the knife holder 130 retracts into engagementwith the detent 139 on the cartridge housing 121 to hold the knifeholder 130 and knife 126 in this retracted position. The driver 131 isretained in its distal most (fired) position by engagement of the detentpost 140 on the driver 131 engaging detent 142 of the cartridge slot137.

Should there be an interference on the knife 126, as from the usercutting into another surgical instrument by mistake, such that the forcefrom the firing bar return spring 55 is insufficient to retract thefiring bar 43 and thus retract the knife 126 into the cartridge housing121, the user can manually retract the cutting system by pullingclockwise on the firing trigger 27. The manual clockwise movement causesthe arcuate firing trigger link 51 to rotate clockwise until it strikesa firing bar retraction tab 71 on the proximal end 47 of the firing bar43. The contact between the clockwise moving arcuate firing trigger link51 and the firing bar retraction tab 71 causes the firing bar 43 toretract proximally and return to the position shown in FIG. 17. This inturn causes the retraction hook 45 retract the retraction ledge 173 onthe knife holder 130 and knife 126. Thus, this safety feature allows forthe user to retract the cutting mechanism to a safe position and returnthe firing system to a position that would allow the linear surgicalstapler 20 to be opened, as will now be described.

Referring to FIG. 19, when the surgeon depresses the release button 61,the release pall 59 pivots about a release trunnion 63 in a clockwisedirection to dislodge the pall lug 60 from the closure detent 58position. As it is dislodged, the pall lug 60 rides on the toggle arms69 to bypass the intermediate detent position 57 on clamp link 40. Inthis manner, the closure and firing triggers 26, 27 can return to theiroriginal, unactuated positions in response to the bias created from theclosure spring 42 and firing bar return spring 55. When the pall lug 60rides on the toggle arms of the toggles 68, the toggle arms 69 rotatecounterclockwise as the closure and firing triggers 26, 27 rotate in aclockwise direction to return to their original unactuated positions.Therefore, the surgeon can release the closure and firing triggers 26,27 so that they can return to the positions illustrated in FIG. 20without unnecessarily returning to the intermediate detent 57 position.

The release of the linear surgical stapler 20 to the open position shownin FIG. 20 causes the closure member 28 and the attached lockout lever181 to retract to the full open position as shown in FIG. 36. In thisposition the post 188 on the driver 131 is no longer disposed to holddown the lockout lever distal end 185. The driver 131, as describedabove, has been detented into place in the forward position by post 140and the cartridge detent 142. Hence, when the lockout lever 181, whoseproximal end 184 slides along support arm surface 86, is fully retractedit is now free to rotate counter-clockwise and drop lockout groove 187below ledge 85 on the C-shaped supporting structure 81. The lockoutlever 181 will remain in this position when the cartridge module 120 isremoved as shown in FIG. 37.

Any future attempt to close the linear surgical stapler 20 which hasbeen fired will result in the lockout groove 187 hooking into the ledge85 as shown in FIG. 38, supplying feedback to the user of a previouslyfired device. This same feature will engage if the retainer 160 has beenremoved prior to loading and the cartridge module 120 has been misloadedwithout the cartridge module 120 being in the right position. In thiscase the driver post 188 would not be in the right position to movelockout lever 181 into the position to be cammed up onto surface 86 asdescribed above. Similarly, a cartridge module 120 which has alreadybeen fired would also not release the lockout mechanism 180. It isimportant to note that there is closure stroke travel allowed in thelockout mechanism 180 prior to engagement of the lockout groove 187hooking into the ledge 85. This travel indicates to the user that thedevice is not jammed due to some malfunction as might be the reaction ifthe lockout mechanism 180 had no travel. Hence, the user knows that thedevice is not jammed but incorrectly loaded when the lockout mechanismengages.

After release of the device back to the open position shown in FIGS. 1and 2, the retaining pin mechanism 100 must be manually retracted bypulling proximally on saddle 101. The retraction causes the retainingpin 125 to retract back into the cartridge housing 121. At thecompletion of the manual retraction the fired cartridge module 120 canbe unloaded and replaced with a new cartridge module 120.

While the preferred embodiments have been shown and described, it willbe understood that there is no intent to limit the invention by suchdisclosure, but rather, is intended to cover all modifications andalternate constructions falling within the spirit and scope of theinvention.

1. A surgical instrument adapted for applying a plurality of surgicalfasteners to body tissue, the surgical instrument comprising: acartridge module including a cartridge housing containing a plurality ofsurgical fasteners and a knife, the cartridge module includes a driverdisposed to push surgical fasteners out of the cartridge housing; afiring mechanism associated with the cartridge housing for ejecting thesurgical fasteners and the knife from the cartridge housing; and theknife includes a detent disposed to contact a mating detent of thecartridge module during longitudinal travel of the knife therebypreventing undesired forward and rearward motion of the knife; thedriver includes a detent disposed to contact at least one mating detentformed on the cartridge module for preventing undesired movement of thedriver; and wherein the cartridge housing includes a cartridge slotthrough which the detent of the knife extends, the cartridge slotincludes first and second flexible fingers molded into the side of thecartridge housing.
 2. The surgical instrument according to claim 1,wherein the first and second fingers are oriented parallel to thelongitudinal axis of the cartridge module.
 3. The surgical instrumentaccording to claim 1, wherein the first finger is shaped and dimensionedto contact the detent of the knife.
 4. The surgical instrument accordingto claim 1, wherein the second finger is shaped and dimensioned tocontact the detent of the driver.
 5. The surgical instrument accordingto claim 1, wherein cam surfaces are positioned along the edge of eachof the first and second fingers.
 6. The surgical instrument according toclaim 5, wherein the location of the respective cam surfaces isdetermined by the desired position of the driver or knife duringoperation.
 7. A surgical instrument adapted for applying a plurality ofsurgical fasteners to body tissue, the surgical instrument comprising: acartridge module including a cartridge housing containing a plurality ofsurgical fasteners and a knife, the cartridge module includes a driverdisposed to push surgical fasteners out of the cartridge housing; afiring mechanism associated with the cartridge housing for ejecting thesurgical fasteners and the knife from the cartridge housing; means forpreventing undesired forward and rearward motion of the knife to preventthe knife from inadvertently moving; and means for preventing undesiredmovement of the driver.
 8. The surgical instrument according to claim 7,wherein the means for preventing undesired movement of the driverprevents the driver from moving prior to use so that surgical fastenersare not inadvertently fired.
 9. The surgical instrument according toclaim 7, wherein the means for preventing undesired forward and rearwardmotion of the knife includes a detent disposed to contact a matingdetent of the cartridge module during the longitudinal travel of theknife and the means for preventing undesired movement of the driverincludes a detent disposed to contact at least one mating detent formedon the cartridge module.
 10. The surgical instrument according to claim9, wherein the cartridge housing includes a cartridge slot through whichthe detent of the knife extends, the cartridge slot includes first andsecond flexible fingers molded into the side of the cartridge housing.11. The surgical instrument according to claim 10, wherein the first andsecond fingers are oriented parallel to the longitudinal axis of thecartridge module.
 12. The surgical instrument according to claim 10,wherein the first finger is shaped and dimensioned to contact the detentof the knife.
 13. The surgical instrument according to claim 10, whereinthe second finger is shaped and dimensioned to contact the detent of thedriver.
 14. The surgical instrument according to claim 10, wherein camsurfaces are positioned along the edge of each of the first and secondfingers.
 15. The surgical instrument according to claim 14, wherein thelocation of the respective cam surfaces is determined by the desiredposition of the driver or knife during operation.
 16. A surgicalinstrument adapted for applying a plurality of surgical fasteners tobody tissue, the surgical instrument comprising: a cartridge moduleincluding a cartridge housing containing a plurality of surgicalfasteners and a knife, the cartridge module includes a driver disposedto push surgical fasteners out of the cartridge housing; a firingmechanism associated with the cartridge housing for ejecting thesurgical fasteners and the knife from the cartridge housing; means forpreventing undesired forward and rearward motion of the knife to preventthe knife from inadvertently moving; and wherein the driver includes aprefired position and a retracted position and means are operativelyassociated with the driver for securing the driver in the prefiredposition and means are operatively associated with the driver forsecuring the driver in the retracted position.
 17. The surgicalinstrument according to claim 16, wherein the means for preventingundesired forward and rearward motion of the knife includes a detentdisposed to contact a mating detent of the cartridge module during thelongitudinal travel of the knife and the means for securing the driverin the prefired position and the means for securing the driver in theretracted position includes a detent disposed to contact at least onemating detent formed on the cartridge module.
 18. The surgicalinstrument according to claim 17, wherein the cartridge housing includesa cartridge slot through which the detent of the knife extends, thecartridge slot includes first and second flexible fingers molded intothe side of the cartridge housing.
 19. The surgical instrument accordingto claim 18, wherein the first and second fingers are oriented parallelto the longitudinal axis of the cartridge module.
 20. The surgicalinstrument according to claim 18, wherein the first finger is shaped anddimensioned to contact the detent of the knife.
 21. The surgicalinstrument according to claim 18, wherein the second finger is shapedand dimensioned to contact the detent of the driver.
 22. The surgicalinstrument according to claim 18, wherein cam surfaces are positionedalong the edge of each of the first and second fingers.
 23. The surgicalinstrument according to claim 22, wherein the location of the respectivecam surfaces is determined by the desired position of the driver orknife during operation.
 24. A surgical instrument adapted for applying aplurality of surgical fasteners to body tissue, the surgical instrumentcomprising: a cartridge module including a cartridge housing containinga plurality of surgical fasteners and a knife, the cartridge moduleincludes a driver disposed to push surgical fasteners out of thecartridge housing; a firing mechanism associated with the cartridgehousing for ejecting the surgical fasteners and the knife from thecartridge housing; means for preventing undesired forward and rearwardmotion of the knife to prevent the knife from inadvertently moving; andwherein the driver includes a prefired position and a retracted positionand means are operatively associated with the driver for securing thedriver in the prefired position and for securing the driver in theretracted position.
 25. The surgical instrument according to claim 24,wherein the means for preventing undesired forward and rearward motionof the knife includes a detent disposed to contact a mating detent ofthe cartridge module during the longitudinal travel of the knife and themeans for securing the driver in the prefired position and the retractedposition includes a detent disposed to contact at least one matingdetent formed on the cartridge module.
 26. The surgical instrumentaccording to claim 25, wherein the cartridge housing includes acartridge slot through which the detent of the knife extends, thecartridge slot includes first and second flexible fingers molded intothe side of the cartridge housing.
 27. The surgical instrument accordingto claim 26, wherein the first and second fingers are oriented parallelto the longitudinal axis of the cartridge module.
 28. The surgicalinstrument according to claim 26, wherein the first finger is shaped anddimensioned to contact the detent of the knife.
 29. The surgicalinstrument according to claim 26, wherein the second finger is shapedand dimensioned to contact the detent of the driver.
 30. The surgicalinstrument according to claim 26, wherein cam surfaces are positionedalong the edge of each of the first and second fingers.
 31. The surgicalinstrument according to claim 30, wherein the location of the respectivecam surfaces is determined by the desired position of the driver orknife during operation.